Magnetic materials, including magnetic materials comprising a thermoplastic, are well known. One use of such materials is as a part of a closure system (e.g., a woman's purse with a magnetic catch). Typically, such magnetic materials in conventional closure systems are in the form of rigid metal magnets or flexible magnetic tapes that are attached to articles through various mechanical and/or adhesive means. See, for example, U.S. Pat. Nos. 4,200,547 and 6,312,795 and published U.S. Pat. No. 6,749,551 and US 2005/0015069.
Such closure systems have various problems with respect to use in a personal care article. For example, the cost of the equipment necessary to position, attach (and, if necessary, cut) a flexible, bonded magnetic material to the product can be excessive. Further, such magnetic materials are limited in shape availability or other desirable properties for use in a personal care article. For example, metallic magnets are available in many shapes but are relatively expensive, particularly for application to a single use personal care article. Further, such metallic magnets have limited mechanical flexibility which is also desirable for many personal care articles.
On the other hand, flexible materials of the art are typically manufactured using a calendering process or extruded in a ribbon form. As will be recognized, such processes result in a substantially planar two dimensional form for the flexible magnetic materials. As will also be recognized, such a two dimensional form can be cut into a shaped configuration by known methods, such as die cutting. However, since the magnetic material is formed in a separate step such material, even if it is somewhat flexible still needs to be applied to a substrate for use in many personal care articles. As is well known, the apparatus (e.g., cut and slip technology) for such application for single use personal care articles is both mechanically complex and expensive. It is also necessary to provide means (e.g., an adhesive) to attach the magnetic material to the substrate.
Three dimensional structures are also known where a polymer magnetic particle blend is injection molded to form an article. However, such preformed structures also must be placed and adhered to a substrate using additional manufacturing steps similar to those discussed above for application of flexible magnetic materials.
Printing magnetic materials is also known. However, such printed materials are said to comprise a magnetic ink where magnetic particles are dispersed in a vehicle and printed onto a substrate using known techniques such as screen printing. As will be recognized printing processes carry the burden of environmental undesirability due to the generation of volatile organic carbon and other effluents. Also, the presence of a vehicle limits the concentration of magnetic particles that may be incorporated into the ink due to the increase in viscosity as solids level increases with the resulting need to provide enough vehicle to maintain a printable composition because, as will be recognized, the vehicle is then evaporated in a separate drying/curing step.
Thus there is a need for improved personal care articles and articles of commerce comprising such personal care articles in suitable packaging where either the personal care article or the packaging is provided with a magnetic feature.
There is a further need for magnetic features with a high magnetic flux density that can be applied to a substrate using relatively simple process apparatus such a printing.
There is still a further need for flexible magnetic features that have a relatively complex three dimensional configuration so as to provide added benefits to users of personal care articles such as improved conformity to an underlying complex three dimensional shape or mechanical interlocking of a matched pair of magnetic elements.